You would need something like this, or third party alternative for 1/3 of the cost: https://www.apple.com/shop/product/HMUJ2...

The connectors look very standard so it shouldn’t cost much to make, but in typical Apple fashion the officially sanctioned kit’s price is set to unapologetically profitable level.

But from repairability viewpoint this is bad because the standard parts (CPU and RAM) are the parts that are least likely to fail, whereas the parts that might fail (motherboard, power supply, etc) most are all proprietary and difficult or impossible to get.

So 1 point comes off from having a proprietary SSD, but no points come off from having proprietary motherboard and proprietary power supply? Makes sense.